In many applications, it is advantageous to construct conduits, such as tubes or channels, from rigid or flexible materials. Flexible conduits have proved popular in part because they are relatively simple and inexpensive to produce, particularly if constructed from sheet materials which can be heat sealed together at longitudinal edges thereof to form the conduit, and are deformable to facilitate storage or deployment of the conduit in compact or irregularly shaped areas. Because such conduits are economically produced, they are particularly suitable for applications where it is desirable to dispose of the conduit after use. For example, in medical applications, it is desirable that conduits be disposed of after contact with drugs or body fluids.
A problem encountered in this regard is the lack of one-way flow devices suitable for use in both rigid and flexible conduit applications. Desirably, such a device should be simple and inexpensive to construct so that it may be economically employed in connection with a disposable apparatus. In addition, it is desirable that the device continuously and automatically respond to conditions in the conduit, without the need for manual implementation, particularly if the device is deployed in a relatively inaccessible region. Finally, it is desirable that the one-way flow device be constructed without the sliding or rotating parts associated with some known valves, as such parts may stick in an open or closed position. As can be appreciated, the latter concern may be of critical importance in medical applications.
One known one-way flow device is disclosed in U.S. Pat. No. 2,926,692. The one-way flow device allows discharge of fluid from a rigid core. A flexible sealing member, which is attached to the core, supports a closure button. When fluid flows from the core through an aperture, the flexible member opens outwardly to permit fluid flow. However, when the flow from the core ceases, the flexible member collapses allowing the button to cover the aperture, the flexible member and button thereby preventing backflow into the core.
Another flow regulating device is disclosed in U.S. Pat. No. 3,057,373. The device shuts off fluid flow through a line when the flow rate reaches a predetermined value. In an open position, the free end of a leaf spring overlies an aperture. The aperture is closed, thereby shutting off flow through the line, by deflection of the leaf spring occasioned by a pressure drop associated with an increased flow rate through the line.
Another known flow regulating device is disclosed in U.S. Pat. No. 4,230,149. The device regulates the flow rate through a line to maintain a substantially constant flow rate. A cantilevered reed is disposed with a free end adjacent to an aperture through which fluid passes. The reed deflects in response to changes in the differential pressure thereacross associated with changes in the flow rate through the line, thereby changing the size of the opening through which the fluid flows and regulating flow through the line.
However, these patents do not disclose a simple one-way flow device for use in conduits constructed from rigid pipes or flexible sheet materials. Thus, there is a need for such a device which is simple and inexpensive to produce so that it may be economically employed in connection with a disposable apparatus. In addition, there is a need for such a device which continuously and automatically responds to conditions in the conduit. There is also a need for such a device that functions without the sliding or rotating parts associated with some known valves.